I have a manager, I have completed scripts, but I don't have any momentum going in my writing career. What's missing? What do I need to do to get over the hump and become a working writer?
What a great question! So many times writers plateau because they concentrate only on writing. Not that it's a bad thing to be writing: the more scripts you write, the better you get and the more you have to sell. But you need to be careful to nurture the marketing aspect of your career as well.
So, given where you are, there are three possible stumbling blocks:
1) Your writing might not yet be strong enough. Usually the thing keeping you from the top tier is either that your stories aren't structure tightly enough or that your dialogue still rings just a little flat. Get feedback from trusted sources: your manager, writer friends, producer friends. Each will have their own take on your work; don't take any as gospel, but if you start hearing a theme emerge, address the note.
2) Your scripts may not be commercial enough. This is a tougher problem. I think you should with write your own voice and driven by your own passion. If mainstream producers don't share your vision, you're going to need to dig around for the producers who do. Festivals and competitions like Sundance have done a lot to raise the profile of Independent films. Research directors, producers, actors and other writers who share your sensibility and develop contacts in that world. On the other hand, a case can be made to write something commercial and use it to leverage your other ideas. "Scream" allowed Kevin Williamson to do "Dawson's Creek." Once you're hot, even your quirky ideas look a lot more viable to the Powers That Be.
3) Finally (and most likely), you might not have enough contacts to really get your foot in the door. I know, I know, the image of a writer is Joan Wilder in Romancing the Stone, hiding behind her computer and ill-at-ease navigating a business lunch, much less the wilds of Columbia. But to write in the film and television industries, you have to play well with others. Who you know matters because you need to get read to get optioned. Join writers groups, go to parties, take seminars, go out and meet as many different kinds of people as you can. Also, take matters into your own hands and research who might produce your script and then call them up and see if they'll take a pitch, either over the phone or in a meeting.
In any event, the person you should sit down with to strategize is your manager. Start building a team of friends and fans. And of course, do keep writing.
It seems to me that the worst thing that can happen is that you get a staff job on a TV series, and at the end of your twelve-week (or whatever) contract, they decide not to pick you up. What can you do about it?
Huh. That's the worst thing? To actually get to spend 12 weeks doing the thing you've been trying to do for years and being paid extremely well for it? I understand your point, but this does call for a little perspective: this is a very good problem to have.
The thing to do, of course, is to plan for it. You will be fired. It's inevitable, and in television it's usually sooner rather than later. Even Friends finally got cancelled, right? So you have to plan to be out of work at some point.
The key is to continue marketing yourself while you're working. It's like the Oscars before the envelope is opened: everyone is a winner until that moment. Until you're fired, you're a staff writer and people are going to be congratulating you. Make friends with the other writers on the staff, as well as the producers, the assistants, the actors. Don't be phony, just be yourself and genuinely try to get to know others. Some you won't like, but most you will, and a few will become good friends.
Also, this is to the time to network outside your show. Take breakfast meetings, have drinks, host a weekend brunch for every newly-minted staff writer on every show. You'll all be at the same level so no one will feel they're being schmoozed, and by gum you'll all have great war stories to share!